In top of double boiler, whisk together egg yolks, sugar and cognac.
Place pan over simmering water.
Cook, whisking constantly, until mixture is thickened, about 2 to 3 minutes.
Cool.
In large bowl of electric mixer, beat yolk mixture and Ricotta cheese on medium speed until blended.
Fold in whipped cream.Place 32 ladyfinger halves in bottom of 13x9-inch pan, cut side up.
Brush with half of coffee; spread with half of Ricotta mixture.
Repeat layers.
Chill 2 hours.
Just before serving, dust with cocoa; cut into squares.
Garnish with Chocolate Curls.